U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
To reach the tidal bench marks from the U.S. Post Office and court house on
Second Street, proceed north one block to C Street, proceed one block west to
First Street, proceed about 0.3 mile (0.5 km) north along First Street to where
it runs into Railroad Avenue, and continue north along Railroad Avenue following
the signs to ferry dock. The bench marks are located in the vicinity of the
ferry dock and extend south along Railroad Avenue toward Cordova. The tide
station is a 6 foot by 9.5 foot room within a lone red building located at the
SE corner of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING:
MONUMENTATION: VM#: 14015
AGENCY: PID:
SETTING CLASSIFICATION:
BENCH MARK STAMPING: 4050 M 1977
MONUMENTATION: Survey Disk VM#: 1232
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set flush in a 4 x 4-foot concrete slab in front of the SW
door of the Ferry Terminal Building at the intersection of Ocean Dock Road and
Orca Road, 41 feet (12.5 m) SE of the centerline of Ocean Dock Road, 36 feet (11
m) north of the centerline of Orca Road, 17.3 feet (5.3 m) east of utility pole
No. 74, 4.5 feet (1.4 m) SSE of the SW corner of the terminal, 2.0 feet (0.6 m)
ESE of the WNW side of the slab, and 1.2 feet (0.4 m) NNE of the SSW side of the
slab.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4050 E 1982
MONUMENTATION: Survey Disk VM#: 1233
AGENCY: PID#: UW7940
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set near the inshore end of the ferry dock, 160 feet (48.8 m)
east of the tide station, 14.4 feet (4.4 m) SE of the SE inshore end of the
approach to the ferry dock, 2.6 feet (0.8 m) SW of an iron guardrail, and 0.5
foot (0.2 m) NW of a 4 x 4-inch wooden witness post. The bench mark is set 0.2
foot (0.2 m) below grade, crimped to a galvanized steel rod driven 48 feet (14.6
m) and is encased in a 4-inch PVC pipe.
BENCH MARK STAMPING: NO 9 1964
MONUMENTATION: Survey Disk VM#: 1234
AGENCY: PID:
SETTING CLASSIFICATION: Bedrock
The bench mark is set flush in a bedrook outcrop north of the staging area on
the Morpac Cannery dock, 28 feet (8.5 m) west of the SW corner of the two-story
blue and white house, and 9 feet (2.7 m) east of the base of the radio antenna
mast on the same outcrop.
BENCH MARK STAMPING: NO 13 1970
MONUMENTATION: Survey Disk VM#: 1237
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Dock
The bench mark is set flush in the SW corner of the concrete surface of the
Cordova Municipal Dock, 3.5 feet (1.1 m) south of a dock bollard, 1.5 feet (0.5
m) east of a red light, and 0.5 foot (0.2 m) north of the south end of the dock.
The bench mark is set 1 foot (0.3 m) above the wharf floor.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4050 F 1982
MONUMENTATION: Survey Disk VM#: 1238
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set along the east side of Ocean Dock Road, 725 feet (221 m)
south of the inshore end of the ferry dock, 433 feet (132 m) south of Bench Mark
4050 M 1977, 174 feet (53 m) NE of a group of pipes leading over a bluff to an
oil tank farm, 29.2 feet (8.9 m) east of the centerline of the Ocean Dock Road,
and 2.0 feet (0.6 m) north of utility pole No. 71. The bench mark is set 0.3
foot (0.1 m) below grade, crimped to a galvanized steel rod driven 9 feet (2.7
m) to refusal, and is encased in a 4-inch PVC pipe.
BENCH MARK STAMPING: 4050 G 1982
MONUMENTATION: Survey Disk VM#: 1239
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set along the east side of Ocean Dock Road, 420 feet (128 m)
south of Bench Mark 4050 F 1982, 86.9 feet (26.5 m) east of the east side of the
corrugated metal Morpac Cannery Warehouse, 25.0 feet (7.6 m) east of the
centerline of Ocean Dock Road, and 2.3 feet (0.7 m) south of utility pole No.
68. The bench mark is set 0.3 foot (0.1 m) below grade, crimped to a galvanized
steel rod driven 14 feet (4.3 m) to refusal, and is encased in a 4-inch PVC
pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4050 H 1982
MONUMENTATION: Survey Disk VM#: 1240
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set along the east side of Railroad Avenue, 192 feet (58.5 m)
SE of the SE corner of a large light brown metal corrugated warehouse building,
23.5 feet (7.2 m) east of the centerline of Railroad Avenue, and 2.0 feet (0.6
m) north of utility pole No. 61. The bench mark is set 0.3 foot (0.1 m) below
grade, crimped to a galvanized rod driven 30 feet (9.1 m), and is encased in a
4-inch PVC pipe.
BENCH MARK STAMPING: NO STAMPING 1
MONUMENTATION: Survey Disk VM#: 1241
AGENCY: PID:
SETTING CLASSIFICATION: Pipe Mark
The bench mark is set on the centerline of Railroad Avenue, 915 feet (278.9 m)
NE of Bench Mark NO STAMPING 2, 59 feet (18 m) NE of the NE corner of a light
brown and white A.P.A. net storage shet, and 27.5 feet (8.4 m) SW of a fire
hydrant located next to utility pole No. 64. The bench mark is set 0.5 foot
(0.2 m) below the road surface. (Note: Bench mark was historically referred to
as B (1980).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO STAMPING 2
MONUMENTATION: Survey Disk VM#: 1242
AGENCY: PID:
SETTING CLASSIFICATION: Pipe Mark
The bench mark is set on the centerline of Railroad Avenue, 387 feet (118.0 m)
north of Bench Mark NO STAMPING 3, 167 feet (51 m) SW of the intersection of
Ocean Dock Road and Railroad Avenue, 90 feet (27.4 m) west of utility pole No.
57 along Ocean Dock Road, and 16 feet (4.9 m) east of the south end of a
guardrail along the west side of Railroad Avenue. The bench mark is set 0.5
foot (0.2 m) below the road surface and is covered by a 0.6 foot (0.2 m)
diameter iron plate stamped 5680 OFCO SEATTLE MON. (Note: Bench mark was
historically referred to as C (1980).
BENCH MARK STAMPING: NO STAMPING 3
MONUMENTATION: Survey Disk VM#: 1243
AGENCY: PID:
SETTING CLASSIFICATION: Pipe Mark
The bench mark is set on the centerline of Railroad Avenue, 443 feet (135 m)
north of a 100-foot (30 m) tall red and white striped antenna, 169 feet (51.5 m)
north of a sewer manhole cover No. 5942, and 33 feet (10.1 m) west of the end of
a 2-foot (0.6 m) diameter drain pipe lying above ground between Railroad Avenue
and Ocean Dock Road. The bench mark is set 0.5 foot (0.2 m) below the road
surface and is covered by a 0.6 foot (0.2 m) diameter iron plate stamped 5680
OFCO SEATTLE MON. (Note: Bench mark was historically referred to as D (1980).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO STAMPING 4
MONUMENTATION: Survey Disk VM#: 1244
AGENCY: PID:
SETTING CLASSIFICATION: Pipe Mark
The bench mark is set on the centerline of Railroad Avenue, 358 feet (109.1 m)
south of Bench Mark 4050 H 1982, 81.4 feet (24.8 m) north of Bench Mark NO
STAMPING 5, 29.3 feet (8.9 m) NW of utility pole No. 58, and 20.9 feet (6.4 m)
east of a steel guardrail. The bench mark is set 0.3 foot (0.1 m) below the
road surface and is covered by a 0.6 foot (0.2 m) diameter iron plate stamped
5680 OFCO SEATTLE MON. (Note: Bench mark was historically referred to as J
(1982).
BENCH MARK STAMPING: NO STAMPING 5
MONUMENTATION: Survey Disk VM#: 1245
AGENCY: PID:
SETTING CLASSIFICATION: Pipe Mark
The bench mark is set on the centerline of the intersection of Railroad Avenue
and First Street, 150.5 feet (45.9 m) NE of Bench Mark NO STAMPING 2, and 77.0
feet (23.5 m) NE of utility pole No. 57. The bench mark is set 0.3 foot (0.1 m)
below the road surface and is covered by a 0.6 foot (0.2 m) diameter iron plate
stamped 5680 OFCO SEATTLE MON. (Note: Bench mark was historically referred to
as K (1982).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
T I D A L D A T U M S
Tidal datums at CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND based on:
LENGTH OF SERIES: 16 YEARS
TIME PERIOD: 1965-1982
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 9451600 SITKA,
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (11/11/1981) = 17.74
MEAN HIGHER HIGH WATER (MHHW) = 12.49
MEAN HIGH WATER (MHW) = 11.58
MEAN TIDE LEVEL (MTL) = 6.53
MEAN LOW WATER (MLW) = 1.47
MEAN LOWER LOW WATER (MLLW) = 0.00
LOWEST OBSERVED WATER LEVEL (04/26/1967) = -4.62
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
0 0.00 0.00
4050 M 1977 24.84 13.26
4050 E 1982 18.58 7.00
NO 9 1964 20.52 8.94
NO 13 1970 21.77 10.19
4050 F 1982 45.26 33.68
4050 G 1982 30.71 19.13
4050 H 1982 30.57 18.99
NO STAMPING 1 28.18 16.60
NO STAMPING 2 34.31 22.73
NO STAMPING 3 25.17 13.59
NO STAMPING 4 35.56 23.98
NO STAMPING 5 38.05 26.47
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
PUBLICATION DATE: 09/12/1984
Station ID: 9454050 SUPERCEDED DATE: 04/21/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SOUND
ALASKA
NOAA Chart: 16710 Latitude: 60° 33.5' N
USGS Quad: CORDOVA (C-5) Longitude: 145° 45.2' W
D E F I N I T I O N S
Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch. It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929. Bench mark elevations relative to NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.
The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed.
The NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum. As a result of
this averaging, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.